This invention relates to a wrist of a robot fitted at a forward end of an arm thereof, which wrist can be flexed along an arcuate path when necessary.
To obtain flexing of a robot wrist along an arc, one only has to mount an oscillating motor at each of the joints located along the length of the wrist. However, disadvantages associated with this arrangement reside in the fact that pipes and wires connecting the oscillating motors to a drive source interfere with an operation of the wrist because they are located outside the wrist. Moreover, mounting the oscillating motors increases the size and weight of the wrist of the robot to the extent corresponding to those of the motors.
One of the objects of the present invention resides in the provision of a wrist of a robot of compact size and light weight which is free from the aforesaid disadvantages of the prior art. Another object of the present invention resides in protecting gears assembled with the wrist of the robot from external shocks. Other and additional objects, features and advantages of the invention will become apparent from the description set forth hereinafter.
This invention pertains to a wrist of a robot of the type in which motive force for obtaining flexing of the wrist along an arc is transmitted successively through portions of the wrist corresponding to joints thereof. In accordance with the invention, the motive force transmitting system includes a gearing of high reliability in performance in which gears are arranged to be disposed inwardly of wrist frames.
The wrist of the robot according to the invention comprises at least more than three wrist frames or first, second, third, . . . and nth wrist frames, with the first wrist frame being fitted to an arm of the robot, the second wrist frame being pivotally connected to the first wrist frame, and the third wrist frame being pivotally connected to the second wrist frame and, if possible, a fourth wrist frame being pivotally connected to the third wrist frame.
The first wrist frame comprises a main stationary gear in meashing engagement with an auxiliary stationary gear of the third wrist frame, with the main stationary gear of the first wrist frame being disposed inwardly of the first wrist frame as well as the second wrist frame. An auxiliary stationary gear, for example, of the second wrist frame is disposed inwardly of the first wrist frame, with a drive means, disposed inwardly of the first wrist frame, being connected to the auxiliary stationary gear of the second wrist frame. By transmitting motive force between the main stationary gears or the drive means and the auxiliary stationary gears, the wrist of the robot can be flexed as a whole along an arcuate path at the joints of the respective wrist frames.